In electronic systems, a heat sink is a passive heat exchange component that cools down a device by dissipating heat into the surrounding medium, such as air. Heat sinks can be used with high-power semiconductor devices such as power transistors and optoelectronic devices such as lasers and light emitting diodes (LEDs), where the heat dissipation ability of the device package is insufficient to control its temperature. A heat sink is designed to increase the surface area in contact with the cooling medium surrounding it, such as the air. Some of the factors which affect the thermal performance of a heat sink include approach air velocity, choice of material, fin (or other protrusion) design, and surface treatment.
In computer devices, heat sinks are used to cool central processing units (CPUs) or graphics processors. For example, in different personal or mobile computer devices, heat sinks can be mounted on printed circuit boards (PCBs), via some thermal interface material. Screws with springs are inserted through the heat sink, thermal interface material, and PCB to hold and firmly affix the different components to each other, which ensures efficient heat transfer from the PCB to the heat sink. However, the screws with springs can affect the heat sink design by introducing cut off on the surface of the heat sink and reducing the space for the fins (or other protrusions), which can reduce overall heat dissipation and thus cause degradation to device performance.